Addition agents



United States Patent 2,767,165 ADDITION AGENTS Herschel G. Smith, Wallingford, and Troy L. Cantrell, Drexel Hill, Pa., assignors to Gulf Oil Corporation, Pittsburgh, Pa'., a corporation of Pennsylvania No Drawing. Application July 3, 1952 Serial N0. 297,164

11 Claims. (Cl. 260-139) This invention relates to addition agents for mineral oil lubricant compositions and, more particularly, it is concerned with addition agents which confer improved antioxidant, detergent and/ or corrosion-inhibiting properties on mineral oil lubricants.

It is recognized in the art that mineral oil lubricants are readily oxidized under service conditions thereby reducing the service life of internal combustion engines. A concomitant effect is corrosion of bearing surfaces. In the lubrication of internal combustion engines of all types, particularly when severe operating conditions are encountered, uncomp'ounded mineral lubricating oils frequently prove unsatisfactory because they tend to deposit varnish, gum and sludge on the engine surfaces, such as the cylinder walls, pistons and rings, and also to induce corrosion of bearing materials thereby causing failure of the engine. These problems have become increasingly series because of the trend toward higher efficiency or higher power output per unit weightof engine, which results in conditions tending to accelerate the deteriorating influences on the mineral oil lubricant. The presence of gums, varnishes and sludges is detrimental for many reasons. These substances tend to increase ring sticking and accelerate the formation of further deposits on piston surfaces and in fixed parts of the combustion chamber. The sludges formed in the crank case of the engine increase the rate of corrosion of bearing surfaces, especially of bearing alloys of the type now in use.

It is an object of this invention, therefore, to prepare an addition agent which will obviate the oxidation and corrosion difficulties encountered in the use of mineral oil lubricants.

It is also an object of this invention to provide mineral oil lubricant compositions which have excellent detergency properties.

In our copending application Serial No. 718,902, filed December 27, 1946, now U. S. Patent No. 2,603,603, of which this application is a continuation-in-part, there is disclosed and claimed an improvement agent for mineral oil lubricants which is prepared by treating an essentially paraffinic base lubricating oil with aluminum chloride and reacting the treated oil with phosphorus pentasulfide to incorporate phosphorus and sulfur therein.

As shown in our copending application, the agent is prepared by heating an essentially parafiinic base lubricating oil, such as may be derived from Pennsylvania, Mid-Continent, or other paraffinic base crudes, with anhydrous aluminum chloride, removing aluminum chloride from the reaction product and reacting said product with phosphorus pentasuliide at an elevated temperature to incorporate phosphorus and sulfur therein. Briefly, treatment with aluminum chloride is accomplished by heating the essentially parafiinic base lubricating oil with from i to 20 percent of anhydrous aluminum chloride at a temperature of from 150 to 300 F. while vigorously agitating, with the time of treatment varying in accordance with the amount of aluminum chloride used and the temperature of treatment, longer-times being required with 2,767 ,l 65 Patented Oct 16, v 1956 less aluminum chloride and lower temperatures In general, however, the treatment will be completed after four or five hours. In any event, treatment is continued until a product is obtained which, when freed of aluminum chloride, will not form a black, difficultly soluble sludgelike product upon subsequent reaction with phosphorus pentasulfide. If desired, the aluminum chloride treated oil may be blended with some of the untreated charge stock without deleteriously affecting the subsequent reaction with phosphorus pentasulfide, but ordinarily not more than about 20 percent of untreated oil should be' added to the treated product and, preferably, smaller amounts should be used. The reaction with phosphorus pentasulfide is accomplished by adding 2 to 20 percent by weight of P285, preferably from 5 to 10 percent, to the aluminum chloride treated oil, or the blend With untreated oil disclosed above, and heating with agitation at a minimum reaction temperature of450 F. and a maximum reaction temperature below the temperature where cracking of the oil, that is, pyrolytic decomposition of the treated oil begins. Generally, the minimum cracking temperature of the oil will vary between 490 to 530 F. depending on the particular oil used. During the course of the reaction with P285, hydrogen sulfide is evolved and phosphorus and sulfur become incorporated in the aluminum chloride treated oil. When the evolution of hydrogen sulfide has nearly ceased, the temperature of the reaction mixture may be increased within the maximum temperature disclosed above, say to about 50 F. for completion of the reaction.

As shown in the aforesaid cop-ending application, if the prior aluminum chloride treatment of the oilis omitted, a black, poorly soluble, sludge-like product is obtained upon subsequent reaction with the phosphorus pentasulfide. Similar unsuitable products are obtained if a hydrocarbon other than an essentially paraflinic base oil is employed as the initial material, regardless of prior treatment with aluminum chloride.

In our U. S. Patent No. 2,456,336, granted December 14, 1948, there is disclosed and claimed an improvement agent for mineral oil lubricants which is prepared by reacting an essentially paraffim'c base lubricating oil, of the type described above, with phosphorus pentasulfide in the presence of a surface active silica-containing solid catalyst. It is shown in the patent that when phosphorus pentasulfide is reacted with an essentially parafil-nic base lubricating oil in the presence of a surface active silicacontaining solid catalyst, the prior aluminum chloride treatment of the lubricating oil, as disclosed in our copending application Serial No. 718,902, may be omitted. It is also shown in the patent that when the prior aluminum chloride treatment of the oil is combined with reaction of the treated product with phosphorus pentasulfide in the presence of the silica-containing catalyst, lighter colored products are obtained. The reaction of the essentially paraffinic base lubricating oil, Whether or not treated with aluminum chloride, with phosphorus pentasulfide in the presence of the silica-containing catalyst is accomplished by adding from 2 to 20 percent by weight of P285, preferably from 5 to 10 percent, to the essentially paraffinic base lubricating oil and heating with agitation at a temperature in the range from 300 F. to'a maximum reaction temperature below the temperature where cracking of the oil begins. The surface-active, silica-containing solid catalyst is employed in an amount of from 2 to 25 percent of the oil, and preferably in an amount of 10 percent by weight. Larger amounts than 10 percent are ordinarily not necessary, but larger amounts will produce a product having a lighter color. During the course of the reaction, hydrogen sulfide is evolved and phosphorus and sulfur become incorporated in the oil. When the evolution of hydrogen sulfide has nearly ceased, the temapplications Serial No. 31,598, filed June 7, 1948, now

U. S. Patent No. 2,603,600, Serial No. 37,308, filed July 6, 1948, now U. S. Patent No. 2,603,601, and Serial No. 73,218, filed January 27, 1949, now U. S. Patent No. 2,603,602, We have disclosed and claimed improvements over the inventions set forth in our copending application Serial No. 718,902 and our U. S. Patent 2,456,336. Mineral oil lubricants containing the addition agents disclosed in application Serial No. 718,902 and Patent 2,456,336 sometimes fail to pass the well-known Copper Strip Test (Method 530.31, Federal Specification VVL791c, May 12, 1945, page 259), thus indicating the presence of elementary sulfur or the so-called corrosive sulfur. In accordance with our U. S. Patent 2,593,496 and our copending applications Serial No. 31,598, Serial No. 37,308 and Serial No. 73,218, we found that the incorporation of a sulfur acceptor in the preparation of the agents of Serial No. 718,902 and Patent 2,456,336 resulted in new addition agents passing the Copper Strip Test and otherwise improved.

In our Patent 2,593,496, the sulfur acceptor is an ester having the formula:

wherein R and R1 represent aliphatic hydrocarbon radicals, at least One of said radicals containing olefinic unsaturation, and the sum of the carbon atoms of both R and R1 being :not less than 16. The ester is ordinarily added in proportions ranging from 1.0 to 10 percent by weight of the reaction mixture, suiiicient to combine with free or corrosive sulfur from the phosphorus pentasulfide reaction product. Among the esters which are used are those in which both R and R1 have olefinic unsaturation, particularly sperm oil which provides an excellent source of this type of ester. Other specific esters are disclosed in the patent.

In our copending application Serial No. 31,598, the sulfur acceptor is a rnonohydric alkylated phenol having at least 4 carbon atoms in an alkyl group. The alkylated phenol is ordinarily added in proportions ranging from 5 to 50 percent by weight of the parafiinic bas'e lubricating oil, or the aluminum chloride treated product thereof, sufficient to remove free or corrosive sulfur from the phosphorus pentasulfide reaction product. The preferred alkylated phenols are the monohydric alkylated phenols having from 4 to 12 carbon atoms in a branched chain alkyl group, particularly paratetramethylbutyl phenol, other specific alkylated phenols being shown in the application.

In our copending application Serial No. 37,308, the sulfur acceptor is an alkylated phenyl phosphite which may be prepared according to U. S. Patent 2,253,227 to Cantrell and Turner. The alkylated phenyl phosphite is ordinarily added in proportions ranging from to 75 percent'by weight of its mixture with the parafinic base lubricating oil, or the aluminum chloride treated product thereof, sulficient to remove free or corrosive sulfur from the phosphorus pentasulfide reaction product. The

alkyla-ted phenyl phosphites employed are preferably those having from 4 to 8 carbon atoms in a branched chain alkyl group and containing from 1 to 5 percent by Weight of combined phosphorus. Paratetramethylbutyl phenyl phosphite is a preferred material; other specific phosphites are shown in the application.

In our copending application Ser. No. 73,218, the sulfur acceptor is an alkyl orthophosphate having at least 5 carbon atoms in the alkyl group. The alkyl orthophosphate is ordinarily added in proportions ranging from 10 to percent by weight of its mixture with the parafiini'c base lubricating oil or the aluminum chloride treated product thereof, sufiicien-t to remove free or corrosive sulfur from the phosphorus pentasulfide reaction product. The alkyl orthophosphate can be a mono-, di-, or tri-alkyl ester of orthophosphoric acid having the following general formulas:

wherein R represents a saturated aliphatic hydrocarbon radical of at least 5 carbon atoms, preferably 8 to 18 carbon atoms. The upper limit of 18 carbon atoms is not critical, it being dictated by considerations of commercial availability. In the diand tri-alkyl esters the Rs may be the same or different alkyl radicals. A preferred ester is trioctyl phosphate; other specific esters are shown in the application.

The objects of the present invention are accomplished by providing salts of the phosphorus pentasulfide-essentially paraffinic base lubricating oil reaction products of our copending application Serial No. 718,902 and our Patent 2,456,336, whether or not these products have been treated with sulfur acceptors in accordance with our Patent 2,593,496 and our copending applications Serial No. 31,598, Serial No. 37,308 and Serial No. 73,218. We have found that the foregoing reaction products possess sufficient acidity to enable their neutralization with bases and that the salts so obtained are effective improvement agents for mineral oil lubricants. The desired'salts can also be obtained by metathesis of an alkali metal salt of such reaction products and a water-soluble salt of a metal other than an alkali metal.

The salts of the present invention are easily prepared by simple neutralization with an inorganic base or an organic nitrogen base, or by metathesis, if desired. For example, alkali metal and ammonium salts can be prepared by neutralizing the reaction products of our patents and copending applications, referred to above, with a hydroxide or carbonate of an alkali metal such as sodium, potassium, lithium, ammonium, etc. The alkaline earth metal hydroxides, i. e., calcium, barium, magnesium and strontium hydroxides, yield a particularly preferred group of salts. Aluminum hydroxide is also suitable. Salts of these metals as well as salts of zinc, copper, tin, lead, iron, cobalt, nickel, manganese, cadmium, mercury, bismuth, vanadium, chromium, and the like can conveniently be prepared by metathesis of a water-soluble salt of such metal with an alkali-metal salt of the desired phosphorus pentasulfide reaction product.

Organic nitrogen bases yield valuable addition salts. Such bases include primary, secondary and tertiary aliphatic and aromatic amines and heterocyclic nitrogen bases. Primary alkyl amines such as ethyl, butyl, amyl, hexyl, cyclohexyl, heptyl, octyl, decyl, undecyl, dodecyl, tetradecyl, hexadecyl, octadecyl and eicosyl are suitable. Mixtures of primary alkyl amines, such as are present in commercially available amines derived from fatty acids by well known methods, make desirable salts. For example, cocoamine, derived from coconut oil fatty acids and containing primarily dodecyl amine with smaller amounts of homologues, yields a preferred salt. Primary alkenyl amines corresponding to the primary alkyl amines, such as undecenyl, oleyl, etc., can also be employed. A preferred group is the primary alkyl or alkenyl amines having from 8 to 22 carbon atoms. Salts derived from secondary and tertiary amines, whether aliphatic or aromatic, such as the diand tri-ethanolamines, dicylohexylamine, N-alkyl and N-dialkylarylamiues, e. g., N- ethylaniline, N-dimethyla'niline are satisfactory, as are primary aryl, aralkyl and cycloalkyl amines such as ani line, benzylamine and c'yclohexyl'amine. A valuable class or" salts is derived from heterocyclic nitrogen bases, such as pyridine, picoliiie, ethylpyridine, lutidine, aldehydine, parvoline, quinoline, quinaldine, lepidine, i'soquinolin'e, nicotine, piperidine, morpholine, N-phenyl morpholine, and the like. H

The following examples illustrate the preparation of our new improvement agents. Unless otherwise stated, all parts are by weight.

Example 1 Three thousand (3000) gallons of a solvent-refined dewaxed para-ffinic base lubricating oil were charged to a vessel equipped with an agitator and means for heating and cooling, and agitated at 275 F. while adding 4 percent by weight of anhydrous aluminum chloride. Agitation was then continued for 4 hours. At the end of this time agitation was stopped and the bulk of the aluminum chloride settled in a sludge at the bottom of the vessel. The sludge was withdrawn; and in order to remove any remaining dispersed aluminum chloride in the body of the oil, there was added 0.2 pound-pergallonof oil of an adsorbent clay, such as- SupenFi-ltrol, and the mixture agitated at 210 F. The mixture was then filtered and there was obtained, in a yield of 84.1 percent by volume of the original charge, an aluminum chloride treated oil free of aluminum chloride and having a viscosity index of 105. To 81 parts by volume of the treated oil, there were added 19 parts by volume of the original untreated oil and, of this mixture, 8550 parts were placed into a reaction vessel equipped with an agitator and means for heating and cooling. Then 450 parts of phosphorus pen tasulfide were added with agitation and the temperature was raised to 450 F. A large volume of hydrogen sulfide was evolved and when evolution of hydrogen sulfide had nearly ceased, the temperature was raised'to'500 F. to complete the reaction. The reaction withphosphorus pentasulfide from the time of its addition to the completion of the reaction took 8 hours.

Three thousand (3000) parts of the above product were then heated to 150 F. and102 parts ofcalcium hydroxide were added in the form or an aqueous'slurry. The mixture was heated to 180 F. for half an hour and dried at 280 F. for one hour. The whole was then diluted with 3000 parts of aparatiinic lubricating oil having a viscosity of 70 S:U.S; at 1000 F. and filtered through diatomaceous earth. The product had-the following properties:

Gravity, API 25.8 Viseo'sity, SUS:

100 F. :1 210 52.6 Color,- AiSTM Union r A e l jar l Sulfur, B, percent 1.2 8 Ash, percent 2.05 Neutralization value, ASTM D97448T, Strong base NO. 1.86

Example 11 An identical portion of the phosphorus pentasuliide' and aluminum chloride treated mineral lubricating oil, as described in Example I, was reacted with 300 P 115 f barium hydroxide octahydrate with agitation at 180 F. for 1 hour. Then 3000 parts of a lubricatiifg oil having a viscosity of 70 S. U. S. at 100 F. was added and the whole filtered through diatomaceous' earth. The pr'dduct I hadthe following properties:

thousand 3000) parts or a hosphorus pentas'ul fide and aluminum chloride treated minerailubricating oil, as described in Example I, were reacted with 300 parts of c'ocoar'nine in the manner of the preceding examples with' respect to reaction with calcium hydroxide and barium hydroxide and diluted with 3000'parts of a lubricating oil having a viscosity of 70 S. U. S'. at F.

The product had the following properties:

Gravity, API 27.11 Viscosity, SUS, 210 F 50.7 C olor,ASTM U n 8.0 Sulfur, B, perc nt 1.17

Neutralization-value, ASTM- D974-48T, strong base Example H Fifty-one (51) parts of. an essentially paratfinic baselubricating oil (SAE 30) whichhad been treated with aluminum chloride in accordance with our copefiding ap-' plication Serial No. 718,902 were placedin a reaction vessel with 5.6 parts of phosphorus pentasulfide. The nixture was then. agitated and heated to 450 F. fof a period of 2 hours. The temperature was then gradually raised to 525 F. over a period of 4 hours and maintained at that point for 2 lioi1r s. The mixture was then cooled to 350 F. and 5.1 parts of sperm oil added. Themix ture was held at this temperature for 4 hour's, then cooled and diluted with an equal weight of a light lubricating oil, thereby forming a concentrate of the product. I

Three thousand partsof theabove reactionproduct were, heated to 250" F. and parts of a 5 percent slurry of in water were added, the whole agitated att l80 F. forhalf an hour, then dried at- 280" F. and filtered through' diatorfiaceo'us earth. The product had the following properties;

Gravity, API 21.5

Into'a reaction vessel there were placed 50 parts of an essentially parafiinic base lubricating oil which had been treated with aluminum chloride in accordance withour copending application Serial No. 718,902, 50 parts by weight of octyl (parat''traniethylbutyl) phenyl phosphite and 12.5 parts of phosphorus pentasulfide. The whole was heated to" 400 F. with agitation for 2 hours until the evolution of h d'regen sumde had substantially subsided. With coiitinued agitation, the temperature of the reactiofi mass was then raised to" 520 F. and held at this point for approximately 6 hours. The reaction product was then cooled to 180 F. and 17 parts of barium hydroxide octahydrate in an aqueous slurry were added. The mixture was slowly heated to 280 F. and held at this temperature for 1 hour to remove formed and added water. The mixture was then diluted-with an equal weight of a lubricating. oil having a viscosity of 70 S-. U. S at 100 F. and filtered through diatoniaceous earth. The product had the following properties:

Gravity; API 16.0 Viscosity, SUV, sec., 210 F 69.2

*7 Example VI-- In the presence of parts of an activated montmorillonite as a catalyst, 50 parts of an SAE 30 Mid-Continent paraflinic base lubricating oil and 50 parts of tri secondary-octyl phosphate were reacted with parts of phosphorus pentasulfide. The mixture Was agitated and the temperature raised to 490 F. and held at that temperature for a period of .2 hours. After this time the evolution of hydrogen sulfide had subsided and with continued agitation the temperature was raised to 520 F. and held there for 6 hours to complete thereaction. The mass was then filtered through diatomaceous earth to remove the clay-catalyst. The filtrate was then reacted with 2.5 parts of calcium hydroxide in the form of an aqueous slurry. This reaction was carried out by raising the temperature to-250 B for aperiod of 30 minutes. The product was then filtered through diatomaceous earth to give a filtrate with the following properties:

Although the preceding examples have shown the use of certain bases and reactants in preparing the salts of the present invention, it will be understood that the other bases and reactants disclosed herein may be substituted for the materials of the specific examples to yield satisfactory products.

The salts obtained in accordance with the present invention are excellent improvement agents for mineral oil lubricant compositions. They are readily soluble in all types of mineral oils, that is, paraflinic, naphthenic or mixed base mineral oils and can be blended with such oils in high proportions. This excellent solubility of our new improvement agents permits of the preparation of concentratedsolutions,whichmay, then be diluted down to the proportion desired in the final mineral oil lubricant composition. i, ,The salts of the present invention confer one or more advantageous propertiesron the mineral lubricating oils with which they are incorporated, such as antioxidant, bearing corrosion-inhibiting and rust inhibiting properties. For these purposes our new improvement agents are generally added to mineral oils in minor amounts, say from 0.1 to 25 percent by weight of the mineral oil, sufiicient to confer the desired eifect. V

The following examples illustrate the use of our new agents to obtain improved mineral oil lubricant compositions:

Example VII An improved motor oil, SAE 20, was prepared by blending 2 parts by weight of the agent prepared according to Example I and 98 parts by weightof an SAE grade lubricating oil base. Propertiesof the improved and unimproved motor oil are as follows:

Example VIII Unimproved Improved Lubricant Lubricant Gravity, "API 29. 0 28. 8 Viscosity, SUS, 100 F 335 342 Color, ASTM Union 4. 25 4. 50 Oxidation and Bearing Corrosion Test, Method 257, Gulf:

Duration of Test, Hr 48 48 Oil Bath Temperature,

F 347 847 Air Rate, MLIHr 2, 000 2, 000 Quantity of Oil, M1 300 300 Bearing Type Cd-Ag Ou-Pb Cd-Ag CuPb Wt. Change, Grams. -0. 2319 0. 0867 0. 0032 0. 0109 Wt. Change, Percent. 1.28 0. 38 0. 005 0. 05

Example IX Similarly, an improved motor oil was prepared by blending 2 parts by weight of the additive prepared according to Example III and 98 parts by weight of a solvent refined SAE 20 grade motor oil base. The properties of the improved and unimproved motor oil are as follows:

Unimproved Improved Lubricant Lubricant Gravity, API 29. 0 29. 1 Viscosity, SUS, 100 F 335 337 Color, ASTM Union 4.25 4.0 Oxidation and Bearing Corrosion Test, Method 257, Gulf:

Duration of Test, Hr. 48 48 Oil Bath Gemperature,

. F 347 347 Air Rate, M1./Hr 2, 000 2, 000 Quantity of Oil, M1 1 500 3:00 Bearing Ty'pe Cd-Ag Gu-Pb Cd-Ag Cu-Pb Wt. Change, Grams. 0. 2319 0. 0867 0. 0071 0. 0317 Wt. Change, Percent. 1. 28 0. 38 0. 01 0. 15

Example X An improved motor oil was prepared by blending 2 parts by weight of the additive prepared according to Example IV and 98 parts by weight of a solvent refined motor oil base stock. The properties of the improved and unimproved motor oil are as follows:

Unimproved Improved Lubricant Lubricant Gravity, API 29. 0 29. 0 Viscosity, SUS, F. 335 339 Color, ASTM Union 4. 25 4. 50 Oxidation and Bearing Corrosion Test, Method 257, Gulfz' Duration of Test, Hr 48 48 Oil Bath Temperature,

"F 347 347 Air Rate, M1./Hr 2, 000 2, 000 Quantity of Oil, M1 300 300 Bearing Type Cd-Ag Cu-Pb WCd-Ag Ou-Pb Wt. Change, Grams 0. 2319 0. 0867 0. 0015 0. 0341 Wt. Change, Percent. 1.28 0. 38 0.002' 0. 015

' Example XI An improved motor oil was prepared by blending '1 part by weight of the additive prepared according to Example V with 99 parts by weight of a solvent refined paratfinic motor oil base stock. Comparison of the properties of the improved lubricant and the base lubricant follows:

Uniniproved Improved Lubricant Lubricant Gravity, A110,, 28,8 28.6 Viscosity", SUS, 100 F 352 342 Color, ASTM Union 4. 4. Oxidation and Bearing Corrosion Test, Method 257, Gulf: 7

Duration of Test, Hr 48 48 Oil Bath Temperature,

F 347 347 Quantity of Oil, Ml 300 300 Air Rate, ML/Hr 2; 000 2, 000

Bearing Type Cd-Ag Cu-Pb Cd-Ag Cu-Pb Wt. Change, Grams 0. 2040 0. 3150 0. 0013 0. 026 Wt. Change, Percent. 0. 93 1.42 0. 01 0. 12 Appearance pitted pitted bright coated Chevrolet 36 En, Engine Test, CBC Designation L-4:

Engine Condition Rating- 75 94 Bearing Loss, Mg./W hole Bearing 541 54 Example XII An improved motor oil was prepared by blending 1 part by weight of the additive prepared according to Example VI with 99 parts by weight of a solvent refined paraflinic motor oil base stock.

Comparison of the properties of the improved and the unimproved motor oil are as follows:

Unimproved Improved Motor Oil Motor Oil Gravity, APT 29.0 28. 9 Viscosity, SUS, 100 F 449 453 Color, ASTM Union 4. 25 4. 5 Oxidation and Bearing Corrosion Test, Gulf 257:

Duration of Test, Hr 48 48 Oil Bath Temperature,

F 347 347 Air Rate, MLIH! 2, 000 2, 000 Quantity Oil Used, ML. 300 300 Bearing Type Cd-Ag Ou-Pb Cd-Ag Cu-Pb Wt. Change, Grams 0. 204 0. 3150 0. 0013 0. 031 Wt. Change, Percent- 0. 93 1. 42 0. 01 0. 14

Copper Strip Test passes passes The Oxidation and Bearing Corrosion Test, Method 257, Gulf referred to in the foregoing examples is conducted as follows: An alloy bearing shell of certain commonly used standard dimensions is submerged in 300 ml. of the oil or oil composition to be tested in a 400 ml. Pyrex beaker and heated in a thermostatic oil bath to 347 F. Air is then bubbled through the oil in contact with the bearing shell at a rate of 2000 ml. per hour. At the end of 48 hours the loss of weight and condition of the bearing shell are determined, the bearing shell being washed free of oil and dried before weighing. When determining the effectiveness of various improvement agents, the usual procedure is to run a blank test simultaneously with the oil composition being tested, employing for that purpose a sample of the untreated oil. in this test it is advantageous to employ commercial bearing shells. These shells comprise a suitable metal backing faced with the alloy bearing metal. In this way the actual bearing face is subjected to severe deterioration conditions. By comparison of the results of such tests with actual service tests, we have found them to be in substantial agreement as to the suitability of particular lubricants.

As shown in the above examples, the addition of our new improvement agents to mineral oil lubricant compositions confers excellent antioxidant and bearing corrosion inhibiting properties. At the same time, the com- 10 positions so obtained are stable in storage and use and have a color which is substantially unaffected by the addition of the improvement agent. I

While we have shown in the examples the preparation of compounded lubricating oils, our invention is not limited thereto but comprises all mineral oil lubricant compositions containing our new improvement agents, such as greases and the like. Furthermore, conventional addition agents, such as viscosity index improvers, antifoam agents, pour point depressants and the like may be added without departing from the spirit of the invention.

Resort may be had to' such modifications and variations as fall within the spirit of the invention arid the' scope of the appended claims.

We claim:

1. An addition agent for mineral oil lubricants coniprising a salt selected from the group consisting of alkaline earth metal salts and primary aliphatic amine salts, said primary aliphatic amine having from 8 to 22 carbon atoms, of a product prepared by heating an essentially paraflinic base lubricating oil with anhydrous aluminum chloride at a temperature of from to 350 F., removing almninum chloride from the reaction product, and reacting the latter with phosphorus pentasulfide at a temperature of from 450 F. to a maximum temperature below the minimum cracking temperature of said reaction product to incorporate phosphorus and sulfur therein.

2. The addition agent of claim 1, wherein the phosphorus pentasulfide reaction product has incorporated therein a sulfur acceptor.

3. The addition agent of claim 1, wherein there is additionally employed in the preparation of the phosphorus pentasulfide reaction product a surface active silica-containing soild catalyst.

4. An addition agent for mineral oil lubricants comprising a salt selected from the group consisting of alkaline earth metal salts and primary aliphatic amine salts, said primary aliphatic amine having from 8 to 22 carbon atoms, of a product prepared by heating an essentially paraflinic base lubricating oil with phosphorus pentasulfide in the presence of a surface active silica-containing soild catalyst at a temperature of from 300 F. to a maximum temperature below the minimum cracking temperature of said lubricating oil to incorporate phosphorus and sulfur therein.

5. The addition agent of claim 4 wherein the phosphorus pentasulfide reaction product has incorporated therein a sulfur acceptor.

6. An addition agent for mineral oil lubricants comprising an alkaline earth metal salt of a product prepared by heating an essentially paraflinic base lubricating oil with anhydrous aluminum chloride at a temperature of from 150 to 300 F., removing aluminum chloride from the reaction product, reacting said product with phosphorus pentasulfide to incorporate phosphorus and sulfur therein, and then further reacting the resulting product at a temperature of from 300 to 400 F. with an ester having the formula:

RC-OR1 wherein R and R1 represent aliphatic hydrocarbon radicals, at least one of said radicals containing olefinic unsaturation, and the sum of the carbon atoms of both R and R1 being not less than 16.

7. The addition agent of claim 6, wherein the alkaline earth metal is calcium, and the ester is sperm oil.

8. An addition agent for mineral oil lubricants comprising an alkaline earth metal salt of a product prepared by heating an essentially paraffinic base lubricating oil with anhydrous aluminum chloride at a temperature of from 150 to 300 F., removing aluminum chloride from the reaction product, and reacting the latter with an alkylated phenyl phosphite and phosphorus pentasulfide at 11 a temperature of from 300 F. to a maximum temperature below the minimum cracking temperature of said reaction product to incorporate phosphorus and sulfur therein.

9. The addition agent of claim 8, wherein the alkaline earth metal is barium, and the alkylated phenyl phosphite is para-tetramethylbutylphenyl phosphite.

10. An addition agent for mineral oil lubricants comprising an alkaline earth metal salt of a product prepared by reacting an essentiallytparalfinic base lubricating oil and an alkyl orthophosphate having at least 5 carbon atoms in an alkyl group with phosphorus pentasulfide in the presence of a surface active, silica-containing solid catalyst at a temperature of from 300 F. to a maximum temperature below the minimum cracking temperature of said oil to incorporate phosphorus and sulfur therein.

References Cited in the file of this patent UNITED STATES PATENTS 2,206,151 Bennett July 2, 1940 2,424,402 Loane July 22, 1947 2,456,336 Smith et a1. Dec. 14, 1948 2,593,496 Smith et a1 Apr. 22, 1952 2,603,601 Smith et al. July 15, 1952 2,603,602 Smith et a1. July 15, 1952 2,603,603 Smith et a1. July 15, 1952 

1. AN ADDITION AGENT FOR MINERAL OIL LUBRICANTS COMPRISING A SALT SELECTED FROM THE GROUP CONSISTING OF ALKALINE EARTH METAL SALTS AND PRIMARY ALIPHATIC AMINE SALTS, SAID PRIMARY ALIPHATIC AMINE HAVING FROM 8 TO 22 CARBON ATOMS, OF A PRODUCT PREPARED BY HEATING AN ESSENTIALLY PARAFFINIC BASE LUBRICATING OIL WITH ANHYDROUS ALUMINUM CHLORIDE AT A TEMPERATURE OF FROM 150* TO 350* F., REMOVING ALUMINUM CHLORIDE FROM THE REACTION PRODUCT, AND REACTING THE LATTER WITH PHOSPHORUS PENTASULFIDE AT A TEMPERATURE OF FROM 450* F. TO A MAXIMUM TEMPERATURE BELOW THE MINIMUM CRACKING TEMPERATURE OF SAID REACTION PRODUCT TO INCORPORATE PHOSPHORUS AND SULFUR THEREIN. 